Fatty acid metabolism in hibernatingCepaea nemoralis (Mollusca: Pulmonata)

Lipids: Their Distribution and Metabolism

“…Fatty acid metabolism in C. nemoralis has been studied intensively by Van der Horst. Van der Horst et al (1974) also studied lipid synthesis during hibernation. Fatty acids were synthesized at high rates (Van der Horst, 1973), palmitic acid being the main end product of de novo synthesis.…”

Lipid metabolism of the yellow clam,Mesodesma mactroides: 2‐Polyunsaturated fatty acid metabolism

“…The clam converts linoleic acid to 20:2 (n-6), but no radioactivity was detected in ~/-linotenic and arachidonic acids, indicating no measurable A6-desaturation activity. Efficient elongation of linoleic acid to 20:2 has been demonstrated in the land mollusc Cepaea nemoralis (20) also desaturated the acid, synthesizing 20:3 (n-6) and arachidonic acid.…”

“…Experiments with rats (15)(16)(17)(18)(19)(20)(21) and fish (22) have shown that the acids 20:5 (n-3) and 22:6 (n-3) are synthesized in the animals from c~linolenic acid by alternate desaturations and elongations similar to linoleic acid.…”

The initial stage of anaerobic metabolism in the snail, helix pomatia L

“…In winter animals the disappearance of lactate introduces a second phase of anaerobic metabolism, involving the formation of succinate and, perhaps, of other end products, whereas spring animals are unable to cope with conditions of prolonged anoxia and lactate begins to rise again. The disappearance of lactate must, of course, be paralleled by an equally rapid removal of pyruvate -either by the pathways leading to succinate [l] or by anaerobic decarboxylation to acetyl-CoA as suggested [9] . Acetyl-CoA could give rise to the synthesis of fatty acids, the energy required for this process being supplied by the first spurt of glycolysis.…”

“…The same is true for alanine which shows a peak synchronous with the lactate peak, increasing from a resting value of 6. the winter snail the formation of lactate provides the energy for the first phase of anaerobic metabolism but is replaced, as the anoxic stress continues, by other anaerobic processes. As far as mollusks are concerned, two such processes have been discussed: the formation of succinate and/or propionate [I] , and fatty acid synthesis [8,9] . The changes in the concentration of succinate in the foot of the winter snails represent, to some extent, a mirror image of the changes in the concentration of lactate and alanine.…”